The colours are in a straight, saturated ramp. Use the search feature for "gold" to see what I mean, it goes through browns to oranges to yellows. You're also used a helluva lot of colours, and they're just put into an up and down gradient. You can still show variation in a symmetrical thing through shading, here's something I whipped up:
I've also dropped the colour count from 26 to 14, without touching the blue.
If all else fails, take it to the WIP thread! :)
Nice.
